Described herein is a process for the fabrication of an electronic device. More specifically, described herein are compositions or formulations for forming a film that are used for a hydrolyzable organosilane precursor film formation in a semiconductor deposition process, such as without limitation, in a flowable chemical vapor deposition of silicon oxide.
Alkoxysilane compounds are useful as precursors for silicon-containing films (such as silicon oxide films) deposited by controlled hydrolysis and condensation reactions. Such films can be deposited onto a substrate, for example, by applying a mixture of water and alkoxysilanes, optionally with solvent and/or other additives such as surfactants and porogens, onto a substrate. Typical methods for the application of these mixtures include, without limitation, spin coating, dip coating, spray coating, screen printing, co-condensation, and ink jet printing. After application to the substrate and upon application of one or more energy sources such as, without limitation thermal, plasma, and/or other sources, the water within the mixture can react with the alkoxysilanes to hydrolyze the alkoxide and/or aryloxide groups and generate silanol species, which further condense with other hydrolyzed molecules and form an oligomeric or network structure.
Vapor deposition processes using water and a silicon containing vapor source for flowable dielectric deposition (FCVD) have been described, for instance, in U.S. Pat. Nos. 8,481,403; 8,580,697; 8,685,867; US 2013/0230987 A1; U.S. Pat. No. 7,498,273; U.S. Pat. No. 7,074,690; U.S. Pat. No. 7,582,555; U.S. Pat. No. 7,888,233; and U.S. Pat. No. 7,915,131. Since the Si—C bond is relatively inert towards reaction with water, the resultant network may be beneficially functionalized with organic functional groups which impart desired chemical and physical properties to the resultant film. For example, the addition of carbon to the network may lower the dielectric constant of the resultant film.
U.S. Publ. No. 2010/0164057 (“the '057 Publication”) discloses a full fill trench structure comprising a microelectronic device substrate having a high aspect ratio trench therein and a full filled mass of silicon dioxide in the trench, wherein the silicon dioxide is of a substantially void-free character and has a substantially uniform density throughout its bulk mass. Also described in the '057 Publication is a process for manufacturing a semiconductor product involving use of specific silicon precursor compositions for use in full filling a trench of a microelectronic device substrate, in which the silicon dioxide precursor composition is processed to conduct hydrolysis and condensation reactions for forming the substantially void free and substantially uniform density silicon dioxide material in the trench. The fill process may be carried out with a precursor fill composition including silicon and germanium, to produce a microelectronic device structure including a GeO2/SiO2 trench fill material. A suppressor component, e.g. methanol, may be employed in the precursor fill composition, to eliminate or minimize seam formation in the cured trench fill material.
U.S. Pat. No. 8,227,395 (“the '395 patent”) discloses the use of acetylenic alcohols to reduce defects in patterned semiconductor devices being processed in aqueous rinses.
U.S. Pat. No. 7,741,773 (“the '773 patent”) disclosed the addition of an acetylenic or other surfactant in a sol-gel formulation for coating by printing or other liquid application means to improve wetting of the substrate and filling irregularities in the surface.
US Publ. No. 2012/0161405 (“the '405 Publication”) teaches that solvents and other surfactants may be used in flowable oxide vapor deposition processes with the benefit of compatibilizing (increasing miscibility of precursors). Examples of surfactants taught include alcohols (generically) and specifically ethylene glycol and polyethylene glycol. The '405 Publication, however, does not teach the use of acetylenic alcohols nor acetylenic diols, nor does it teach the benefits of wetting hydrophobic surfaces or preventing de-wetting of surfaces in trenches or on flat surfaces.
One problem that is encountered in the flowable chemical vapor deposition process (FCVD) is incomplete wetting of the substrate, which could lead to non-uniform substrate coverage or incomplete filling of narrow lines, gaps or vias. Further, another problem encountered in the FCVD process is a relatively slow rate of deposition, since certain surfactants may reduce initiation time and increase deposition rate by enabling capillary condensation. While the prior art has used alcohol-based surfactants such as ethanol in FCVD processes, these surfactants have been shown to be ineffective for use in this application due to incomplete wetting.